Autoallergy in chronic rhinosinusitis and its clinical relevance.

The presence of IgE autoantibodies against human proteins ("autoallergy") has been identified in different type 2 inflammation. The aim of this study was to evaluate the presence of autoallergy in chronic rhinosinusitis (CRS) and explore its clinical impact. Cross-sectional study with CRS patients and healthy controls. Three steps were followed: 1) IgE autoantibodies against Fatty Acid Binding Protein (FABP), FABP3 and FABP4, Eosinophil Peroxidase (EPX), and Eosinophil Cationic Protein (ECP) were measured. 2) The allergenic activity of these IgE autoantibodies was evaluated with basophil activation test (BAT) and skin prick test (SPT). 3) Association of these autoantibodies with some clinical outcomes was explored. 22.3% in the CRS group and 12.1% in the control group had at least 1 IgE autoantibody (IgE-AA). In CRS and control group, the most frequent IgE-AA were against EPX (15.9% versus 5.4% p = 0.03) and ECP (12.7% versus 4% p = 0.04). The IgE autoantibodies had allergenic activity according to BAT and SPT. In CRS group, IgE-AA were associated with higher risk of nasosinusal polyps, clinical severity (SNOT22), asthma, and hyposmia. IgG and IgG4 autoantibodies against these human proteins did not present significant differences between CRS and control group or associations with clinical outcomes. IgE autoantibodies are presented in CRS patients and are associated with severe clinical outcomes. Accordingly, autoallergy could be an endophenotype in CRS with clinical relevance as a biomarker of disease activity. Further studies with larger cohorts are warranted to validate these findings.